1. Field
The disclosed embodiments relate to a system for equalizing the braking energies intended for the landing gear of an aircraft in order to distribute the braking energies among the landing gear, by introducing a braking delay between the brakes of the wheels that are subjected to the greatest vertical loads or that are rolling along a less contaminated runway and the brakes that are installed on the wheels that are subjected to smaller vertical loads or that are rolling along a more contaminated runway.
2. Brief Description of Related Developments
The disclosed embodiments are applicable to the field of aeronautics, and, more specifically, are intended for the landing gear of heavy aircraft.
As is known, a single aircraft may have different types of undercarriages: the main wing undercarriage, the main fuselage undercarriage, and the auxiliary undercarriage (the main forward undercarriage). The main fuselage undercarriage consists of one, two, or three sets of landing gear, and the wing undercarriage consists of two sets of landing gear, one mounted under each wing. The forward undercarriage is mounted at the front of the aircraft, near the nose. Each set of landing gear in the main undercarriages includes a set of twin bogeys containing 2, 4, or 6 wheels, the majority of which wheels are equipped with a brake. The forward undercarriage includes a steerable shock absorber equipped with twin wheels.
When an aircraft is in the deceleration phase, in addition to aerodynamic braking and engine braking (reverse thrusters), the main undercarriage participates in the absorption of the energy of the aircraft by means of its brakes. The undercarriage must withstand major loads due to the mass of the aircraft, which applies compressive vertical stress to the landing gear. During the landing of the aircraft or during an interrupted takeoff (each of which flight phases is associated with very high braking-energy levels), the wheels of a single given set of landing gear and the wheels of different sets of landing gear are not subjected to the same vertical loads.
This non-uniform distribution of the vertical loads among the sets of landing gear and among the wheels of a single set of landing gear leads to the application of different braking efforts and thus to different braking energies for each wheel, thereby entailing differential wear on the brakes. The brakes that absorb the largest amounts of energy (i.e., the ones that are more heavily stressed during the deceleration phases) wear out more quickly than the brakes that are less heavily stressed.
This suboptimal situation in terms of wear on the various brakes entails more frequent maintenance of the more heavily stressed landing gear, thus leading to higher overall maintenance costs.